Credit unit



Nov. 3, 1953 R. A. M CALLUM 2,658,171

/ CREDIT UNIT Filed May 17, 1950 3 Sheets-Sheet l IN VEN TOR.

Nov. 3, 1953 R. A. MCCALLUM CREDIT UNIT 3 Sheets-Sheet 2 Filed May 17, 1950 INVENTOR. yViblZl/il l atentecl Nov. 3, 1953 UNITED STATES T OFFICE CREDIT UNIT Robert A. McGa'llum, Clarendon Hills, II-1., as-

signor, by mesne assignments, to AMI Incorporated, alcorporation ofDelaware Application May 117, 1950, Serial No. 162,43.7

.9 Claims. 1

This invention relates to selector systems and has particular application to a selector :system for a coin controlled automatic phonograph, wherein the selection of records is made by depressing one or more manual push buttons, each arranged to energize a separate circuit containing a selector magnet corresponding to the record desired. In such systems it is conventional practice to provide a series of ooinswitches to be actuated by coins of different 'denomina *tions. In most cases there are separate switches for nickels, dimes and quarters, and in most mechanisms the circuits of these coin switches and selector magnets are controlled 'by a unit known in the trade as a credit-unit. It is with the features of such a unit that the present invention deals.

The basic purpose of the credit'unit is to serve as a memory device with respect to the coins deposited in the machine, so that the machine will permit selection and playing of a number of records corresponding to the total value of all the coins deposited. That is, the credit unit may be said to maintain a constant tabulation of credit units; that is, the number of selections that the deposit of any given coin permits.

Ordinarily, in a conventional installation, the unit will be set to permitone play for five cents, two plays for ten cents, and five plays for twenty-five cents, although this may be altered as desired. In any event, the unit functions to total all the coins of diirerent denominations as they are inserted in the coin slots, at the same time deducting one unit for each record played, so that a constant computation of paid credit units is maintained. When the paid credit is exhausted, the unit shuts oi? the machine to prevent further operation until another coin is deposited.

From the above it should be-o'bvious that dependability of operation is particularly essential in this unit of the machine, since the patrons of any establishment in which a machine is located should have assurance that the machine will play the full number of selections to which the users are entitled, but it must also be :designed so that it is not susceptible to deliberate tricks employed in an effort to beat the ;machine. This poses a rather serious problem from an engineering standpoint at best, and the j I problem is further complicated by the fact that machines of this type are installed in many and various locations, so that the actual operating voltage applied to the electrical circuits thereof varies within unusually wide limits. The result ,2 has been that in'selector circuits heretoforeempl'oyed, it has often been possible to beat the machine in a manner to cause more records to be played than are justified by the coins deposited. In many selector systems this may often be accomplished by actuating two or more of the push buttons almost simultaneously, so that two or more of the selector magnets are energized with only one actuation of the credit unit counter.

It is the primary object of the present "invention to provide a novel and improved electromechanical credit -unit which is so designed and arranged that it may be utilized in connection. with conventional coin switches and with a series of push button controlled selector circuits, but when so used will attain anew degree of dependability in operation and'will "largely prevent any possibility of malfunctioning in the manner noted above.

A further object is to provide a mechanism whose performance is uniform in this respect, irrespective of wide variations of operating voltage.

These objects are accomplished in the present invention by the combination, with a ratchet wheel, solenoid actuator and escapemen-t, of an electromagnetic reset switch and a control relay energized through the contacts of the reset switch and arranged in a control circuit therewith, so that it energizes the selector push huttons with an electrical pulse long enough to permit one, but only one, selection to be made.

The manner in which the foregoing functions are accomplished in the present teaching is best explained in connection with the drawings of this specification, wherein:

Figure '-l is a central sectional view of a cred-it unit according to the present teaching;

Figure 2 is a transverse sectional view taken substantially on the plane of the line 2-2 of Figure 1;

Figure 53 is a transverse sectional view taken substantially on the plane of the line 3-3 of Figure 1;

conventional coin switches and with a series of El push button controlled selector magnets. The portion of the circuit included in the credit unit is outlined in broken lines in the figure.

Figures 9, 10, 11 and 12 are schematic wiring diagrams showing successive circuit operations in the order they occur as a coin is deposited and a selection made- The several related mechanical and electromechanical parts of the credit unit are mounted on a common panel III, which, as illustrated, comprises a flat sheet of metal having a bottom portion II folded at right angles thereto, with a front panel I2 extending upwardly in spacedapart parallel relationship with the panel IE! (Figure 2).

The principal moving part of the unit is a toothed ratchet wheel I4 carried on a shaft I5 extending between the panels II] and i2 and journaled for rotation therein. The ratchet wheel I4 is spring urged counterclockwise as viewed in Figure 1 by a light coil spring I6 anchored to a bracket II extending between the panels III and I2. The coil spring I5 extends to a pin I8 on the back face of the wheel I4, and a small pulley I9 is mounted on the shaft I5 at the back side of the ratchet wheel, so that when the wheel is revolved in a clockwise direction, the spring will stretch around the wheel as required, and will always tend to draw the wheel backwardly (in a counterclockwise direction as viewed in the drawings) to the position shown. This position may be designated as the home or zero position of the mechanism; that is, the position it assumes before a coin has been deposited, and after all credit has been exhausted. In this position, an insulating post 2I carried on the wheel I4 opens the credit switch contacts CS and holds them open until the wheel is advanced by the insertion of a coin in the machine.

The wheel I4 is energized by a solenoid S fastened on the inside surface of the panel I2, a pair of selective solenoid stopping coils SI!) and S5 mounted on a bracket 22 on the panel Ill. The electrical connections and mechanical structures of these parts are such that when the solenoid S is energized, the ratchet wheel I4 will be advanced either 1, 2 or 5 teeth, depending on whether the actuating impulse came from the five cent, ten cent or twenty-five cent coin switch of the machine. To this end, the shaft I5 on which the ratchet wheel I4 is mounted is provided with a swinging frame 23 carrying a cross bar 24 and a pivot rod 25 on which an end plate 26 swings. The end plate 26 has a ratchet dog 21 at one end, and stop surfaces 28 and 29 at the other end. When at rest, the plate 26 lies on the lower arm 3I of the bracket 22. The cross bar 24 of the swinging frame 23 extends directly across the operating pin 32 of the plunger 33 of the solenoid S. Thus, when the solenoid S is energized, the plunger 33 and pin 32 move upwardly, striking the portion 24 of the swinging frame 23 and swinging it upwardly around the shaft I5. As this occurs, the dog 2'! of the ratchet engages one of the teeth of the wheel I4, so that as the frame 23 swings, it moves the ratchet dog upwardly until the stroke of the solenoid plunger is interrupted. In the device shown, this takes place when the stop surface 29 of the plate 26 engages a limit stud 34 carried on the bracket 22. This permits the ratchet wheel I4 to move a distance of five teeth, and represents the action of the mechanism in response to a deposit of a twenty-five cent coin. When a coin of ten cent denomination is deposited, the solenoid S is energized in the same way and moves upwardly in the same fashion as before, except that in this instance the winding of the selective solenoid stop SID is also energized so that its plunger 36 projects into the path of the plate 26 and interrupts its motion when the ratchet wheel I4 has been turned a distance equal to only two teeth thereof (Figure 6). The plunger 36 of this stop is normally maintained out of the path of movement of the plate 26 by a light coil spring 31 which has one end hooked over the head portion 38 of the plunger 36, and the other end portion hooked over the head 39 of a stop plunger 4! in the five cent denomination selective solenoid stop S5. This solenoid operates when the unit functions in response to the deposit of a live cent coin, and in this case the solenoid S and the stop winding S5 are simultaneously energized so that the solenoid moves upwardly as before, but its motion is arrested by engagement of the secondary stop portion 23 on the plate 25, with the projecting end of the solenoid plunger M. This limits the movement of the solenoid and the rotary movement of the ratchet wheel I4 to a distance equal to one notch of the ratchet wheel I4. Thus it is seen that by energizing the solenoid S alone, the unit is made to advance the ratchet five notches, while energization of the solenoid and the stop SIU advances it two notches, and energizing the solenoid and stop S5 causes an advance of one notch only.

Whenever the ratchet wheel I4 is advanced by the action of the solenoid, it is held against return movement by the escapement rocker 5!. This escapement rocker is pivotally mounted on a pin 52 extending between the panels I0 and I2, and the rocker is provided with an upper dog 53 and lower dog 54 to engage the teeth of the ratchet in the usual manner. The rocker 5| has a pair of actuating magnets RS positioned to attract the armature portion 55 and momentarily release the ratchet wheel I4, but the rocker is spring biased so that it tends to swing in a counterclockwise direction and hold the dog 53 in engagement with the ratchet teeth. As shown, this spring bias is accomplished by the tension on the spring leaves 56 on which electrical contacts RSI and RS2 are mounted. Thus when the magnet RS is energized, it pivots the rocker 5I clockwise momentarily, releasing the ratchet wheel I4 for one step of counterclockwise movement and momentarily closing the normally open contacts RSI and RS2.

The contacts RS2 are provided on this switch for purposes of altering the credit setting of the unit when desired, but as this is not an essential feature of the present invention, it will not be discussed further herein.

The panel II) also carries a control relay CR, and a pair of copper oxide rectifiers SI and 62, the purpose and function of which will be described more fully in connection with the description of the schematic circuit diagram of the apparatus.

The electrical connections of the foregoing parts are schematically illustrated in Figure 8, wherein the selector magnets, which may be many in number, are represented by windings SMI, SMZ, SM3 to SM39 and SM40, and their respective push buttons are indicated as FBI to PB IIl. One side of the D. C. power line with which the mechanism is used is connected directly to the terminal 53 and thence to the contacts CS and RS2, as well as to the winding CR or the relay and to the common connection between the rectifiers B1 and 62 and solenoid winding S. The negative side of the direct current power line extends from the selector magnets to a terminal es, and then to three coin switches designated as CS5, C825 and CS). The terminal 5 is also connected to contacts RSI, which establish a connection across thel ine through the relay winding OR. The coin switch contacts CS5 are connected directly to the rectifier v6! and to the winding S5 of the solenoid stop. The opposite contact of the coin switch CSIO is connected to the winding SI iI and to the rectifier 62. The windings S5 and SH] are both connected to the junction between the coin switch CS and the solenoid winding The relay contacts CR'I are arranged in circuit between the main credit switch CS and the winding RS of the reset switch, so that the circuit from the positive line terminal 63 extends in series through the main credit switch, relay contacts and reset switch winding to the manually operable push buttons PBI, P132 .and P33, etc. Each of these push buttons is of single pole, double throw type and arranged in the series relationship shown so that whenever any one of the push buttons is manually actuated, it will break the circuit to all of those beyond it .in the series an instant before it closes the o circuit through .its associated selector magnet winding.

From the foregoing it will be seen "that, in addition to the solenoid actuating circuits ex tending from the terminal 63 through the .solenoid windings, solenoid stops and coin switches, the electrical apparatus of the selector system comprises three separate though related circuits. One of these is what we may term a selector circuit, extending from the line .63 through the main credit switch CS, the relay contacts CRI, the resetting switch winding RS and the push buttons and selector magnets to the opposite line terminal 64. A control circuit extends from the terminal 6-3 through the relay winding CR and the resetting switch contacts RSI to the opposite side of the line. In addition to these, there is a circuit which we may term a holding or bridge circuit extending from the positive line terminal 63 through the winding CR and thence through the resistor R to the resetting switch winding RS and on through the push buttons and selector magnets to the negative side of the line.

Operation The operation of the mechanism is initiated by insertion of a coin in the coin slot of the ma chine. This closes one of the coin switches CS5, CS!!! or CSZ'E, depending on the denomination of the coin used. If a twenty-five cent coin has been inserted, the closing of the coin switch C825 will complete a circuit through the solenoid winding '8, and it will move the plunger 33 the full length of its stroke to advance the ratchet wheel 14 a distance of five notches. It will be retained against return motion by the escapement rocker 5|. If a coin of five cent or ten cent denomination has been used, the operation will be the same, except that the solenoid stop S5 or solenoid stop SH) will also be energized, and will act to interrupt the stroke or" the solenoid and limit the advance of the ratchet wheel to one notch or two notches, respectively. In any case, the momentary closing of the coin switch sufficient to insure positive operation of the solenoid by reason of the presence of the rectifiers 6i and 152, which allow a local current to persist in the solenoid and solenoid stop windings for an instant after their external circuit is broken, so that dependable functioning of these parts is obtained even with an extremely short interval of closure of the coin switches (Figure 9) When the ratchet wheel 14 advances one notch or more, the credit switch contacts CS close and remain closed until the credit has been used by the playing of one or more record selections. Thus, when the credit has been established by moving the wheel is one or more notches, a circuit is set up from the positive line terminal -63 through the credit switch CS and the normally closed relay contacts CRI through the resetting switch windings RS and to the series of push buttons and selector magnets associated therewith. A selection can now be made by depressing one of the push buttons to energize one of the selector magnets. As this is done, the resetting switch winding RS is also energized to momentarily release the ratchet wheel and allow it to move one notch in a counterclockwise direction. This deducts one credit unit from the machine (Figure 10).

It has been pointed out in the earlier portion of this specification, however, that it is common practice for users of coin machines to attempt to'beat the machine by simultaneous or nearly simultaneous operation of several of the series of push buttons, in an attempt to energize more than one of the selector magnets with the momentary pulse required to permit the escapement to move back one notch. It is essential, therefore, to provide means for precise regulation of the interval of the selector circuit, so that it is sufiicient to actuate one of the magnets under any conditions (and with 1ine voltage either above or below normal), yet is regu'lated so precisely that actuation of more than one of the magnets is a practical impossibility. This is accomplished in the present teaching by the provision of the control and bridge circuits consisting of the relay CR and resistor R, together with the contacts RSI on the resetting switch RS. With this circuit, the actuation of any push button energizes the winding RS to momentarily release the escapement dogs, but at the same time it closes the circuit through the relay winding CR, whose contacts CR! break the circuit through which the push buttons have been energized. This means that the instant the contact is established through one of the selector magnets, the circuit thereto is broken so that actuation of additional push buttons can have no .further efiect (Figure 11).

It is to be remembered, however, that the action of the contacts RSI is only momentary, and that to prevent removal of more than one credit, it is necessary that the push button circuit1not only be opened, but held in the open condition until the push button has been released. To accomplish this, the circuit is provided with a bridge resistor R between the relay winding CR and the resetting switch winding RS, so that as long as one of the push buttons is held down, there is a circuit completed through the relay winding CR, the resistor R, the resetting switch winding RS and the push button to :a selector snag-net. The current flowing through this circuit is sufficient to energize the relay winding CR and maintain its con-tact CR1 in the open position, but it is not sufficient to have any effect on the resetting switch winding RS. This prevents the resetting switch from operating again until after the push button has been released.

In the preferred commercial embodiment of the invention the relay winding CR has an impedance of 500 chins and the resistor R is of 100 ohm value, while the selector magnets are of 20 ohms and the resetting magnets of 2 ohms. Under these conditions, the current flowing through this relatively high resistance bridge circuit will be effective to hold the relay contacts CR! open, yet will pass so little current that the selector magnet and resetting magnet will be effectively deenergized. The selector circuit is therefore inoperative until the depressed push button is released. As this occurs, the high resistance bridge circuit through the relay winding GR is broken, allowing the contacts CHI to close and place the circuit in condition for other selections until the entire credit is exhausted and the credit switch CS is opened by mechanical action of the ratchet wheel it.

Having thus described. my invention, what I claim as new and desire to protect by United States Letters Patent is:

1. In a selector system, the combination with a selector circuit comprising a series of push buttons, each comprising a single pole, double throw switch; said push buttons being in series relationship with each other and each button being in series with one of a plurality of selector magnets in parallel relation with each other; of a credit circuit comprising a mechanically actu ated credit switch, a reset magnet and a pair of normally closed reiay contacts in series with said switch, reset magnet and the selector maenets and push buttons; together with a control circuit parallel with the selector circuit and comprising an electromagnetic winding for the normally closed relay contacts of the selector circuit, and a pair of contacts responsive to the operation of the reset magnet thereof; together with a bridge connection from the winding of the reset magnet to the relay winding to hold the credit circuit energized only until the selector circuit is broken.

2. In a selector system, the combination with a selector circuit comprising a series of push buttons, each button being in series with one of a plurality of selector magnets in parallel relation with each other; of a credit circuit comprising a mechanically actuated credit switch, a reset magnet and the selector magnets and push buttons; together with a control circuit parallel with the selector circuit and comprising an electromagnetic winding for the normally closed relay contacts of the selector circuit, and a pair of contacts responsive to the operation of the reset magnet thereof; together with a bridge connection from the winding of the reset magnet to the relay winding to hold the credit circuit energized only until the selector circuit is broken.

3. In a selector circuit including a plurality of selector magnets and a series of selector switches therefor, with a credit switch in series therewith, a multiple step ratchet actuating said credit switch, and an electromagnetic stepping escapement for said ratchet, the combination of a control relay having normally closed breaker contacts in series with said credit switch, and an electromagnetic winding for opening said breaker contacts, and contacts responsive to actuation of 8 said escapement for energizing said winding; to gether with a holding circuit connecting said relay winding to said selector switches.

4. In a selector circuit including a plurality of selector magnets and a series of selector switches therefor, with a credit switch in series therewith, a multiple step ratchet actuating said credit switch, and an electromagnetic stepping escapement for said ratchet, the combination of a control relay having normally closed breaker contacts in series with said credit switch, and an electromagnetic winding for opening said breaker contacts, and contacts responsive to actuation of said escapement for energizing said winding.

5. In combination, a selector circuit including a plurality of selector magnets and a series of selector switches therefor, a credit circuit having a credit switch in series with said selector circuit and a multiple step ratchet actuating said credit switch, with an electromagnetic stepping escapement for said ratchet, and a control circuit having normally closed breaker contacts in series with said credit switch and an electromagnetic winding for opening said breaker contacts; with means responsive to energizing of said selector circuit for energizing said control circuit to open said credit circuit.

6. In a selector system including a plurality of selector magnets and a plurality of selector switches connected thereto, with a relatively low resistance selector circuit extending from said system to a source of power, the combination of a control circuit including a relatively high resistance therein, with means responsive to the closing of one of said selector switches to introduce said high resistance into series relationship with said selector system, and means responsive to opening of said switch to reestablish said low resistance circuit to said system.

7. In a multiple selector system including a plurality of selector magnets and a plurality of switches therefor, the combination of a low resistance selector circuit and a relatively high resistance control circuit in parallel with each other and in series with said magnets and selector switches; each of said circuits including a relay, with the contacts of each of said relays in series with the windings of the other.

8. The combination, with an electrical selector including a plurality of selector magnets and individual switches therefor, of a credit unit including a pair of power leads and a selector lead, with a selector circuit between the selector lead and one of said power leads including a pair of normally closed breaker contacts of a control relay and a credit switch in series; and a control circuit extending between the power leads and comprising the winding of said control relay and a pair of normally open breaker contacts in series.

9. In a multiple selector system having a plurality of electromagnetic selector windings, the combination of a plurality of push buttons each consisting of a normally open contact directly connected to one of the selector windings, and a pair of normally closed contacts joined to another push button and establishing a oontinuous series circuit throughout said plurality of push buttons, with one of said pair of normally closed contacts of each button being shiftable to open said series circuit and to engage the contact of the push button connected to the selector winding, said windings and push buttons com prising a portion of a selector circuit including a References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Simon June 15, 1915 Erbe Jan. 26, 1937 Durant Feb. 4, 1941 Mills Feb. 25, 1941 Andres Dec. 9, 1941 Winkler Aug. 19. 1947 

